A daisy chain interconnection is a wye form of electrical interconnection defined between a signal input and a corresponding pair of signal outputs. Typically the input and the outputs are defined by arrays of signal conductors, with a corresponding plurality of signal conductors usually being present in all conductor arrays.
Presently, such interconnections are made in either of two manners, the first using a device known in the art as an insulation displacement contact daisy chain connector, and the second using the intermediary of a printed circuit board.
An insulation displacement contact connector requires a relatively wide center to center spacing between adjacent conductors in a given array. Usually the conductors have spacings of at least 0.050 inch. This relatively wide spacing requirement is necessary to physically accommodate the insulation displacement contact itself. If a greater conductor density (i.e., closer spacing between adjacent conductors) is required either to perform a particular end use or to define a system having particular electrical parameters (cross talk immunity, impedance matching, etc.) the daisy chain connector using the insulation displacement contact cannot be used. Exemplary of a typical daisy chain connector of the insulation displacement type is the device manufactured and sold by Connector Systems Division of E. I. Du Pont de Nemours and Company, Inc. as the "Quickie" TM connector. Another example of a connector for mass termination of flat multiple wire cable using slotted contacts similar to insulation displacement tines is shown in U.S. Pat. No. 4,140,360 (Huber).
Present daisy chain connectors of the insulation displacement type are thus not readily applicable for use with evolving, increased conductor density cable technology, such as the high speed, high density cable manufactured by Gore, Inc. under model TLN 1365. Such high speed, high density cable has signal conductors with 0.050 inches center to center spacing (or less) and have one or two shielding conductors placed between the signal conductors. The term "high speed, high density cable" is used throughout this application to denote such a cable arrangement.
In addition, the presently available insulation displacement contact daisy chain connector is usable only with conductors covered with a jacket of polyvinyl chloride or similar type insulation. Since the evolving high speed, high signal density cables are insulated with a form of coating made from TEFLON.RTM. fluorocarbon resin, a connector of the insulation displacement contact type is not reliable for use with such cables. Instances are known where a portion of a coating of the type used on the high speed, high density cable has become trapped between the tines of an insulation displacement contact, thus effectively insulating the wire in the cable from the contact or seriously impairing the electrical reliability of the contact.
A daisy chain interconnection formed using the circuit board expedient is able to accommodate the tighter conductor spacing and the cable construction used by the high speed, high density cable. However, to form such an interconnection using a board it is necessary to increase the number of terminations involved as well as to utilize tracings on the surface of the board as part of the signal conduction paths. A termination is required between the conductor and the board and the board and its associated connector. Both of these terminations introduce an electrical reflection into the signal path, thus decreasing the integrity of the transmitted signal. The tracings on the board also introduce other electrical variables which diminish the signal integrity. Moreover, use of the board is disadvantageous from the standpoint of manufacturing cost.
Accordingly, in view of the foregoing it is believed to be advantageous to provide a connector adapted to form a daisy chain interconnection using high speed, high density cables without the use of a circuit board and its attendant disadvantages.